The present invention relates to means for securing machine components in a predetermined position relative to one another and has particular application to mounting of rolling bearing assemblies without clearance and preloaded on shafts or the like. The fastening arrangement includes a first ring engaging in an annular groove in the shaft and a second closed ring abutting the machine component which is held in place by the first ring.
U.S. Pat. No. 1,916,233 shows a means for fastening machine components comprising a ring constructed in two parts which is inserted in an annular groove of the shaft whereby the two parts of the bi-component ring after assembly are held together by a wire ring placed on its outside or the axial flange tabs of a sheet metal disc inserted between the machine element and the bi-component ring.
This prior arrangement has several disadvantages and drawbacks. For example, the ring engaging in the groove is constructed in two parts which not only increases the number of components but also presents the problem that with tolerance variations only one of the ring components absorbs the loading force.
Furthermore, an accurate installation of the bearing is only possible by accurate adjustment of the bi-component ring and/or the sheet metal disc and even in this instance the danger exists that under high loading forces, for example, centrifugal forces, the taught wire ring tends to loosen or the tabs of the sheet metal disc which are axially flanged at the outer end bend in this area with the result that the two ring components can therefore be pressed from the annular groove.
German Patent No. 649,793 shows an arrangement for fastening machine elements in housings or the like such as for example, bearing bushings in the bores of fork joints. In accordance with this patent, this is achieved by introducing liquid or a pasty substance in grooves in the machine elements and their carriers which include hollow cavities, which substance hardens to form solid connecting wedges between the elements.
French Patent No. 1,129,720 shows a means for fastening bearing bushings of universal joints by introducing a construction material which can be cast or sprayed into annular grooves machined near the bottom of the bearing bushing in the fork bore. This cast or sprayed material extends radially and partly covers the bottom and axially secures the bearing bushing. Suitable casting or spray type materials include plastics. However, these materials have certain disadvantages and drawbacks in these applications. For example, plastics are not suitable to transmit high axial forces or to continuously absorb impact loads. Furthermore, since most castable materials shrink during cooling, the connection is weak and tends to loosen and is, therefore, inaccurate. Plastic also ages and becomes brittle so that this is also a factor contributing to failure of the connection over a period of time. In view of this, it is clear that this type of fastening is not suitable for bearing applications which are preloaded and are without clearance.
With the above in mind, it is therefore an object of the present invention to provide a fastening means for machine components particularly bearings which are installed without clearance or preloaded on shafts or the like which on the one hand is of a relatively simplified construction and yet provides an accurate and secure mounting even after a prolonged operating time and is capable of absorbing high axial forces. To this end, the fastening arrangement includes a first ring engageable in an annular groove on one of the machine components such as a shaft and a second closed ring arranged on the outside surface of the first ring. The first ring is a one piece annular member and is initially sleeve shaped and thereafter deformed in a radial direction as a result of axially applied pressure during assembly in an annular intermediate space between the outer peripheral surface of the shaft and the second ring is mounted on the shaft in such a way that it engages in the annular groove in the shaft.
By reason of the one piece construction of the first ring which engages in the annular groove, the number of components is reduced. Further, by reason of the fact that the ring is of a deformable material, it is possible to press the ring in an axial direction into the annular gap between the outer peripheral surface of the shaft and the second ring pushed on the shaft in such a way that it fills the intermediate space and in addition enters the annular groove of the shaft and in this way effectively secures the second ring in an axial direction. The second ring therefore functions much like a swage in this respect. When the annular groove is completely filled, relatively high axial forces can be absorbed without the danger that the rings loosen even after prolonged operating time under normal operating forces. As a result of the axial fixing of the second ring during the pressing or swaging of the first ring, it is possible to accurately position the fastening rings in place. Furthermore, in order to obtain a desired preloading in the machine element or part to be fastened, a pretension or preloading force can be applied to the second ring and therefore to the machine element to be fastened independently of the axial deformation pressure on the deformable first ring.
In accordance with one embodiment of the invention, the inner surface of the second ring is constructed in such a way that the material flows inward into the annular groove of the shaft by deflecting the material flow of the deformable ring. Specifically, the second ring is provided with a curvilinear or arcurate section which deflects the material of the initially sleeve-shaped first ring inwardly into the annular groove as it is axially pressed into place.
In accordance with another embodiment, the second ring has a stepped or angular cross sectional configuration defining a shoulder at the end of the expanded bore thereof which is aligned at one end in the groove of the shaft so that as the first ring is pressed axially into the bore, the material of the ring is deformed to fill the annular groove and lock the ring members in the desired axial position for preloading, for example, the inner ring of a bearing assembly mounted on the shaft. This arrangement has the advantage that during deformation of the ring, the axially running leg can elastically expand and the elastic force always presses the formed ring under radial preloading into the annular groove.
In summary, the present invention provides a simple, accurate and secure fastening means even after prolonged operating time which makes the absorption of high axial forces possible. The ring (16) engaging in the annular groove (17) is constructed in one piece and initially sleeve-shaped from deformable construction material and is deformed to some extent in radial direction as a result of axial pressure during assembly in an annular intermediate space (20) between the outside surface (9) of the shaft or the like (10) and the ring (14) pushed on this shaft in such a way that it engages in the annular groove (17) in the shaft or the like (10).